When the middle-Eastern country of Ramat is over-run by anti-monarchist revolutionaries, the surviving heir to the throne, Princess Shaista, is spirited away to safety in a small girls' school, Meadowbank, which is run by the progressive Miss Bulstrode. However, when the bullying games mistress Miss Springer is found stabbed through the chest with a javelin, it appears that Meadowbank may not be the haven it promised to be. As Poirot assists Inspector Kelsey, they begin to find that some of the staff may not be quite what they appear, a situation which is compounded when another teacher, Mademoiselle Blanche is found dead and Princess Shaista is kidnapped from the school. With the princess' life in peril, and the prized rubies of Ramat missing, it is up to Poirot to discover who is the cat among the pigeons.